The invention relates to an apparatus for changing the direction of motion of letters and similar rectangular pieces of mail which are oncoming in the direction of their long edges, in a manner such that they leave in the direction of their short edges.
In mail sorting machines, for example, the pieces of mail are conveyed in the direction of either their long edges or their short edges, depending on the design of the segments of the distributing lines. The conveyance in the direction of the short edges has the advantage that the sought sorting capacity (in letters per unit time) can be obtained with a lower conveying speed, since with the same space in between latters, their width is the determining factor, not their length. However, since as a rule, the initially stacked letters are removed (singled out) from the stack in the direction of their long edges, a device is needed by which the position of direction of motion of the letter is correspondingly changed.
Such an apparatus for changing the direction of motion of letters in the above-mentioned manner is disclosed in German AS No. 11 99 697, for example. The pieces of mail moved in upright position in a conveying line segment in the direction of their long edges run against a fixed stop and are then removed vertically upwardly, thus in the direction of their short edges. As known from experience with that apparatus in use, the vertical conveying line segment is equipped with equidistantly spaced fingers engaging the individual stopped letters at the lower long edge thereof. Therefore, this apparatus is usable only for a conveyance in synchronism, i.e. the pieces of mail must arrive at the fingers with equally spaced leading edges and in definite time intervals.
To avoid this restriction, the removal upwardly had to be effected, for example, by means of a pair of seizing rollers controlled through the arrival of individual letters, which causes problems of wear and noise. Further difficulties arise in both instances from the necessity of braking the letters within a short distance from the full conveying speed to zero speed, and not even the use of a brush roller as provided in the mentioned German AS No. 11 99 697 can completely overcome this problem.